Dual-mode roll/nod gimballed seeker for a forming warhead

Abstract

A dual-mode roll/nod gimballed seeker is configured to provide an unobstructed path for a forming-warhead penetrator. A nod assembly includes first and second seekers separately offset from the roll axis whose FOV overlap within a stand-off range to a target. A roll gimbal rotates the dome and nod assembly around the roll axis. A nod gimbal rotates the nod assembly about a nod axis over a nod FOR that causes the seekers to cross the roll axis and obstruct a path along the roll axis. At terminal, the nod gimbal rotates the nod assembly to a nominal nod angle at which the path is unobstructed to detonate the forming warhead and project a penetrator along the path through the dome. This alleviates the need for a precursor charge and saves precious volume in the airframe, which is of particular import for small diameter warheads, in particular those having a diameter of no more than 8 inches.

We claim: 
     
       1. A warhead and seeker assembly, comprising:
 an airframe having a roll axis and a nod axis perpendicular to the roll axis; 
 a forming warhead positioned within the airframe and configured to project a penetrator forward along the roll axis upon detonation; 
 a roll gimbal positioned forward of the forming warhead; 
 a dome positioned on the roll gimbal to rotate around the roll axis; 
 a nod assembly including,
 a first seeker positioned within the dome, said first seeker having a first FOV that projects forward through the dome; and 
 a second seeker positioned within the dome, said second seeker having a second FOV that projects forward through the dome such that the first and second field of view (FOV) overlap within a stand-off range to target; 
 
 a nod gimbal configured to rotate the nod assembly about the nod axis; 
 wherein said first and second seekers are separately offset from the roll axis such that at a nominal nod angle a path along the roll axis is unobstructed; 
 wherein rotation of said nod assembly about the nod axis over a nod field-of regard (FOR) causes the first and second seekers to cross the roll axis and obstruct the path along the roll axis; and 
 a controller configured such that just prior to detonation of the forming warhead the controller commands the nod gimbal to rotate the nod assembly to the nominal nod angle such that the penetrator moves unimpeded along the roll axis and unobstructed path through the dome. 
 
     
     
       2. The seeker and warhead assembly of  claim 1 , wherein diameters of the airframe and dome are no greater than 8 inches. 
     
     
       3. The seeker and warhead assembly of  claim 1 , where the first and second seekers are fixed with respect to the nod assembly. 
     
     
       4. The seeker and warhead assembly of  claim 1 , wherein the dome includes an aft opening that defines a volume for formation of the penetrator upon detonation of the forming warhead. 
     
     
       5. The seeker and warhead assembly of  claim 4 , further comprising:
 a membrane across the aft opening of the dome to prevent contamination of the first and second seekers. 
 
     
     
       6. The seeker and warhead assembly of  claim 1 , wherein the roll gimbal comprises:
 a ring-shaped roll bearing and roll motor positioned between the airframe and dome to roll the dome about the roll axis without obstructing the path along the roll axis. 
 
     
     
       7. The seeker and warhead assembly of  claim 6 , wherein the roll gimbal further comprises a slip ring positioned between the airframe and the dome to pass electrical signals back-and-forth across the roll gimbal. 
     
     
       8. The seeker and warhead assembly of  claim 1 , wherein the dome includes a middle section positioned between first and second outer sections that project forward from the roll gimbal to rotate about the roll axis, wherein the nod assembly includes the middle section within which the first and second seekers are mounted spaced apart from and on opposing sides of a roll/nod plane at the nominal nod angle, said nod gimbal further including a nod motor positioned on the nod axis in the first outer section of the dome to rotate the nod assembly about the nod axis. 
     
     
       9. The seeker and warhead assembly of  claim 8 , wherein the first and second seekers operate in an EO and an RF band, respectively, wherein the middle section of the dome includes a first window transparent to the EO band opposite the first seeker and a second window transparent to the RF band opposite the second seeker. 
     
     
       10. The seeker and warhead assembly of  claim 8 , wherein the dome has a spherical shape, wherein the first seeker operates in an electro-optical mode and is positioned off-axis from the dome, further comprising an arch corrector positioned between the first seeker and the dome. 
     
     
       11. The seeker and warhead assembly of  claim 8 , wherein the first seeker operates in an electro-optical mode and is positioned off-axis from the dome, wherein the middle section of the dome includes a flat window. 
     
     
       12. The seeker and warhead assembly of  claim 8 , wherein the nod axis passes through a center of the dome such that rotation of the middle section of the dome stays within an outer mold line (OML) of the aircraft. 
     
     
       13. The seeker and warhead assembly of  claim 1 , wherein the entire dome rotates about the roll axis and is fixed with respect to the nod axis, wherein the first and second seekers are spaced apart from and on opposing sides of a roll/nod plane at the nominal nod angle, wherein the nod gimbal includes a nod motor positioned on the nod axis, within the dome to rotate the nod assembly about the nod axis. 
     
     
       14. The seeker and warhead assembly of  claim 13 , wherein the first and second seekers operate in different bands, wherein the dome includes a transparent window transparent to the different bands opposite the first and second seekers as they move relative to the dome through the nod FOR. 
     
     
       15. The seeker and warhead assembly of  claim 1 , wherein the first and second seekers are mounted spaced apart from and on opposing sides of a roll/nod plane at the nominal nod angle such that the penetrator moves along the unobstructed path between the first and second seekers. 
     
     
       16. A warhead and seeker assembly, comprising:
 an airframe having a roll axis and a nod axis perpendicular to the roll axis; 
 a forming warhead positioned within the airframe and configured to project a penetrator forward along the roll axis upon detonation; 
 a roll gimbal including a ring-shaped roll bearing and a roll motor positioned forward of the forming warhead; 
 a dome including a middle section and first and second outer sections that project forward from the ring-shaped motor to rotate around the roll axis, said middle section of the dome having an aft opening that defines a volume for formation of the penetrator upon detonation of the forming warhead; 
 a nod assembly including, 
 the middle section of the dome;
 a first seeker at a fixed position within the middle section of the dome, said first seeker having a first field of view (FOV) that projects forward through the dome; and 
 a second seeker at a fixed position within the middle section of the dome, said second seeker having a second FOV that projects forward through the dome such that the first and second FOV overlap within a stand-off range to target; 
 
 a nod gimbal including a nod motor positioned on the nod axis in the first outer section of the dome to rotate the nod assembly about the nod axis; 
 wherein at a nominal nod angle said first and second seekers are positioned on opposing sides of a roll/nod plane such that a path along the roll axis is unobstructed; 
 wherein rotation of said nod assembly about the nod axis over a nod field-of regard (FOR) causes the first and second seekers to cross the roll axis and obstruct the path along the roll axis; and 
 a controller configured such that just prior to detonation of the forming warhead the controller commands the nod gimbal to rotate the nod assembly to the nominal nod angle such that the penetrator moves unimpeded along the roll axis and unobstructed path through the dome. 
 
     
     
       17. A seeker assembly for use with a forming warhead, comprising:
 a roll gimbal configured to roll around a roll axis; 
 a dome positioned on the roll gimbal; 
 a nod assembly including,
 a first seeker positioned within the dome, said first seeker having a first field of view (FOV) that projects forward through the dome; and 
 a second seeker positioned within the dome, said second seeker having a second FOV that projects forward through the dome such that the first and second FOV overlap within a stand-off range to target; 
 
 a nod gimbal configured to rotate the nod assembly about a nod axis perpendicular to the roll axis; 
 wherein said first and second seekers are separately offset from the roll axis such that at a nominal nod angle a path along the roll axis is unobstructed; 
 wherein rotation of said nod assembly about the nod axis over a nod field-of regard (FOR) causes the first and second seekers to cross the roll axis and obstruct the path along the roll axis; and 
 said nod gimbal responsive to an electrical signal such that just prior to detonation of the forming warhead the nod gimbal rotates the nod assembly to the nominal nod angle such that the penetrator moves unimpeded along the roll axis and unobstructed path through the dome. 
 
     
     
       18. The seeker of  claim 17 , wherein the roll gimbal comprises:
 a ring-shaped roll bearing and a roll motor to roll the dome about the roll axis without obstructing the path along the roll axis. 
 
     
     
       19. The seeker of  claim 17 , wherein the dome includes a middle section positioned between first and second outer sections, wherein the nod gimbal includes a ring coupled to the ring-shaped motor and from which the first and second outer sections are fixed and project forward to rotate about the roll axis, wherein the nod assembly includes the middle section within which the first and second seekers are mounted, said nod gimbal further including a nod motor positioned on the nod axis in the first outer section of the dome to rotate the nod assembly about the nod axis. 
     
     
       20. The seeker of  claim 17 , wherein at the nominal nod angle the first and second seekers are mounted spaced apart from and on opposing sides of a roll/nod plane.